Centrifugal separator



Aug. 31, 1937. A. NYROP 2,091,329

CENTRIFUGAL SEPARATOR Filed Dc. 2, 1955 INVENTOR. AAGE NY RoR BY A TTORNE Y.

Patented Aug. 31, 1937 UNITED STATES PATENT OFFICE Application December 2, 1933, Serial No. 700,687 In Great Britain January 18, 1933 8 Claims.

The present invention relates to centrifugal separators designed to separate sludge from liquids, the term sludge being considered as designating not only impurities, but any material including a large proportion of solids of higher specific gravity than the liquids in which they are suspended.

It relates more particularly to separators of the type in which the bowl is divided into two parts which are adapted to undergo a relative axial movement at periodic intervals to afford provision for discharge of sludge between the bowl parts. Such a separator is described in my prior Patent No. 1,735,692. In the preferred construction described in that patent, a piston is rigidly secured to one of the bowl parts and this piston reciprocates within the other bowl part-intermittently to effect the desired relative movement between the parts. The bowl parts are retained normally in closed position under the influence of spring pressure and are moved intermittently to open position by the admission of operating liquid into communication with the under side of the piston, this operating. fluid acting under the influence of centrifugal force to effect the desired movement of the piston.

The present invention involves an improvement over my prior patent with respect to the sealing connections, piston operating mechanism and other important features of the machine.

An important feature of the invention consists in the arrangement of a flexible gasket or packing ring of novel design surrounding the piston, this ring being loaded with a material of relatively high specific gravity and energized by centrifugal force to increase the sealing pressure during the rotation of the bowl. Such a sealing arrangement effectively precludes the passage of liquid between the source of actuating liquid for the piston and the main body of the bowl.

Another feature of the present invention consists in the actuation of the piston by means of liquid admitted to annular channels adjacent the lower part of the bowl and the provision of a special valve or retardation means for the actuating liquid and a liquid feedarrangement affording provision for. the movement of the piston into bowl-closing or' sludge-discharging position in accordance with the differential forces exerted by the-liquid within the bowl and the liquid introduced to actuate the piston, the valve mechanism or retardation means being itself 'hydraulically actuated and the position of the piston being controlled by the operator by the selective feed of liquid to the piston actuating portion of the machine.

A still further feature of the invention consists in an arrangement whereby the parts of the bowl are held in rigidly spaced relationship with respect to each other and the discharge openings between or in these parts are controlled by the piston itself, the piston coacting directly with a gasket securedto one of the bowl parts to effect the scaling function.

Further features and advantages of the invention will be apparent from a reading of the following detailed description in the light of the attached drawing, in which,

Figure 1 is a central axial sectional view illustrating the principal form of the invention.

Figure 2 is a view similar to Figure 1, illustrating a modified form of the invention.

Referring to the drawing by reference characters, the numeral I. designates the shaft of the machine which may be driven in any suitable manner, as for example, by a Worm and worm-wheel drive. The upper end of this shaft issecured within an opening in an upstanding boss 3 of the lower part 2 of the centrifugal bowl. This lower part of the bowl is provided with an upstanding cylindrical wall 4 which is secured to an upper part 5 in any desired manner, these portions being secured together in spaced relationship in order to afiord provision for a plurality of discharge openings 6 between the parts 2 and 5 of the bowl. An alternative arrangement whereby the exterior sludge discharge slot is arranged within one of the bowl parts instead of between these parts may be adopted, if desired.

The interior of the bowl tapers from both ends toward the middle and has a maximum interior diameter at the zone of junction between its opposed portions 2 and 5 in the neirghborhood of the discharge openings 6. A central distributing feed tube 1 is secured to the bowl in such a position as to feed the material to be treated into the bottom portion of the bowl and a suitable disc inset 8 is also secured within the bowl, the disc inset and distributing tube being secured in place by means of a nut 9 which is threaded on the upper outer circumference of the distributing tube.

Accelerating wings are provided at H and these wings can be fixed to rings 5| in order to facilitate their removal for cleaning. A skimming plate l0 directs the lighter efliuent separated within the bowl to a discharge outlet l3 and a heavier efliuent through openings I2 under the control of an interchangeable weir II. A cylindrical liner I9 is preferably secured within a circumferential groove I5 in the lower part 2 of the bowl and a reciprocating annular piston I6 5 is adapted to reciprocate within this groove.

As pointed out above, the piston I6 is designed for reciprocation in response to the differential pressure between theliquid in the space beneath this piston and in the main body of the bowl.

10 Movement of the piston upwardly into sealing contact with the gasket 3I closes the bowl and movement downwardly out of such sealing contact allows concentrated sludge to be discharged outwardly through the openings 6. In order to effect this reciprocating movement as desired,

the machine is provided with means for selectively admitting and discharging liquid from the space beneath the piston I6. These means include a pair of annular grooves 22 and 23 in the lower part of the bowl and radially extending passages 24 and 25 interconnecting these grooves with a valve chest 26 and the space beneath the piston I6, respectively.

A piston valve 21 may be provided which is 25 adapted to be moved to opposite positions in the valve chest 26 in response to the selective admission of liquid to one of the grooves 22 or 23 through one of the pipes 32 or 33. A plug 28 is threaded into the outer radial end of the valve 30 chest and is provided with a fine bore 34 to afford provision for the discharge of liquid from the chest. Aligned openings 29 establish communication between the space beneath the piston I6 and the valve chest and between the valve 35 chest and the atmosphere beneath the bowl. A

vent opening 30 establishes communication between the inner radial extremity of the chest 26 and the atmosphere beneath the bowl.

In the normal operation of the machine, liquid is admitted to the groove 23 and forced outwardly through passages 25 under the influence of centrifugal force into the lower part of the slot I5. Centrifugal force acting on this liquid within the slot holds the piston I6 firmly against the gasket 3| during the normal rotation of the bowl to effect a concentration of the sludge under treatment and a discharge of purified liquids. During this stage of the operation of the machine, the piston valve 21 is held in the position illustrated in Figure 1 under the influence of centrifugal force, thus preventing heavy discharge of actuating liquid through openings 29 from the groove I5.

When it is desired to discharge accumulated sludge from the bowl, the liquid supply through the pipe 33 is cut off. Liquid may be supplied by the pipe 32 into the groove 22, from which it passes under the influence of centrifugal force through passage 24 into contact with the outer end of piston-valve 21. The piston-valve is thus moved radially inwardly and establishes communication through the passages 29 between the groove I5 and the atmosphere beneath the bowl, thus allowing liquid beneath the piston I6 to be discharged through the passages 29 and permitting the piston to descend under the influence of the centrifugal force exerted upon its upper edge by the liquid within the bowl. It will be appreciated that the pressure of the liquid in the slot I5 acts on area a+b when the piston I6 is in the closed position, whereas the opposed pressure from within the bowl acts only on the area a. This pressure exerted on the area a is, however, sufficient to cause the desired downward movement of the piston when the pressure on the under-side of the piston is reduced by the 'release of the liquid beneath the piston.

When the retarding means constitutes a piston-valve as illustrated and it is desired to shift the bowl parts from open to closed position, the liquid supply through the pipe 32 is-discontinued, thereby permitting the piston-valve 21 to be moved to the position of Figure 1 under the influence of centrifugal force, and the. supply through pipe 33 is resumed. During this movement, liquid within the valve chest 26 is discharged through opening 34. Movement of the valve 21 to the position of Figure l prevents an entirely free discharge of liquid through passages 29. To effect the bowl-closing movement of the piston I6 liquid is admitted through pipe 33 and acts upon the lower end of this piston.

It will be noted that the piston I6 is provided with an extension 35 adapted to be received withing the upper part 5 of the bowl. The gasket 3i is mounted in a part of the upper bowl member 5 at the top of the zone of deflection of the discharging current. The discharging sludge is thus directed across the face of the gasket thereby sweeping the gasket clean and preventing undue sludge accumulation thereupon. The importance of this arrangement will be obvious from the following considerations. If the gasket 3| were mounted directly in the zone of discharge, there would bea strong tendency for solids, to erode the gasket in the course of their discharge radially past said gasket, but by placing the gasket in the position indicated, it is kept clean with only slight abrasions. The arrangement of the gasket and coacting piston I6 in this recessed position also tends to prevent leakage directly through the sealing zone from the bowl. When the gasket is arranged as illustrated, the pressure from within the bowl tends to press the gasket into sealing contact with coacting surfaces instead of tending to destroy that contact, as is sometimes the case with gaskets located approximately in the zone of discharge.

In the practice of the invention, a novel method of packing is adopted for insuring provision against leakage between the piston I6 and the adjacent surfaces of the liner I9 and/or bowl part 2 along which it reciprocates. An important feature of this packing consists in the fact that its normal sealing pressure is reinforced by the action of centrifugal force upon the sealing member itself. To this end, the lower edge of the annular piston I6 is slotted in such a manner as to leave an outer thin and flexible annular lip or rim I8 which may be loaded with lead or other suitable heavy material II. During the rotation of the bowl the flexible lip is subjected to the centrifugal force operating upon the loading material H to force this lip against the adjacent surface of the liner I9. The inner surface of the piston I6 may be packed by a suitable packing ring 20 secured to the bowl part 2 and this packing may be likewise loaded with lead. By reason of this construction, the packing ring 20 is forced against the piston I6 by the action of centrifugal force upon the loading member 2I. It will thus be seen that the loading arrangement I1, I6 with respect to the lower end of the piston and the loading arrangement 20, 2I with respect to the packing ring afford adequate provision against leakage of liquid between the space within the main body of the bowl and the space beneath the piston I6.

In the form of the invention illustrated in Figure 2, the piston I6 is much larger than the piston ii of Figure 1 and has practically all of its inner surface exposed to the pressure of the liquid within the bowl. The piston I6 is provided with a central upstanding boss 35 mounted for reciprocating movement along the long upstanding boss 3 of the lower part 2 of the bowl, a long sliding bearing being thus provided to avoid tilting of the piston. The piston i8 has a flexible packing ring l8 loaded with lead l'l' or the like. The operation of this embodiment of the invention is similar to that of Figure 1, and the liquid may be alternately admitted through the openings 24 and 25 to effect the desired recipld rocating movements of the piston Hi to sludgedischarging and bowl-closing positions, respectively.

While only two modifications of the invention have been described, it will be obvious that many 20 changes may be made without departing from the spirit of the invention as defined in the attached claims.

I claim: 1. A centrifugal separator including a cen- 25 trifugal bowl adapted to be rotated to effect the continuous discharge of a liquid effluent and the concentration of suspended solid material within the bowl, a' piston mounted for reciprocation within said bowl, and means for effecting recip- 30 rocating movements of said piston at desired intervals to afford provision for the discharge of sludge from said bowl, said piston being annularly slit to provide a flexible lip at one of its extremities adapted to seal the piston against leakage of 85 liquid by reason of the action of centrifugal force upon said lip. I

2. A centrifugal separator including a centrifugal bowl adapted to be rotated to effect the continuous discharge of a liquid effluent and the concentration of suspended solid material within the bowl, a piston mounted for reciprocation within said bowl, means for eflecting reciprocating movements of said piston at-desired intervals to afford provision for the discharge of sludge from said bowl, said piston being annularly slit to provide a flexible lip at one of its extremities adapted to seal the piston against leakage of liquid by reason of the action of centrifugal force ,upon said lip, and loading means within said slit adapted to reenforce said centrifugal sealing action.

3. A centrifugal separator including a centrifugal bowl provided with a. discharge opening and adapted to be rotated to effect the continuous discharge of a liquid eflluent during the concentration of suspended solid material within the bowl, said bowl being provided with a long and relatively narrow annular groove, an annular discharge-controlling piston mounted in said groove and adapted to be reciprocated therein against and away from a sealing surface to control the discharge of sludge from the bowl,. hydraulic means for moving the piston to sludge discharging position, hydraulic means for moving the piston to bowl-closing position, and a valve for perv relatively narrow annular groove, an annular discharge-controlling piston mounted in said groove and adapted to'be reciprocated therein against and away from a sealing surface to control the discharge of sludge from the bowl, hydraulic means for moving the piston to sludge discharging position, hydraulic means for moving the piston to bowl-closing position, a valve for permit ting discharge of piston-actuating liquid during the movement of said piston to sludge discharging position, and hydraulic means for controlling the actuation of said valve.

5. A centrifugal separator including a centrifugal bowl provided with a sludge discharge opening and adapted to be rotated to effect the continuous discharge of a liquid effluent and the concentration of suspended solid material within the bowl, said bowl being provided with a long and relatively narrow annular groove, an annular discharge controlling piston mounted in said groove and adapted to be reciprocated therein against and away from a sealing surface to control the discharge of sludge from the bowl, 9; sealing member within said bowl adapted to coact with said piston in the prevention of undesired discharge of sludge from said bowl, a flexible sealing member associated with the portion of the annular groove in the bowl lying inwardly of said piston, and aweighted member associated with said flexible sealing member and adapted to urge said sealing member into sealing engagement with said piston under the influence of centrifugal force upon rotation of the bowl.

6. A centrifugal separator including a centrifugal bowl provided with a discharge opening and adapted to be rotated to effect the continuous discharge of a liquid eilluent during the concentration of suspended solid material within the bowl, a discharge controlling piston within a part of the bowl and adapted to be reciprocated to control the discharge of sludge from the bowl,

' hydraulic means for moving the pistonto sludge discharging position, hydraulic means for moving the piston to bowl-closing position, a valve for permitting discharge of piston actuating liquid during the movement of said piston to sludge discharging position, means for actuating said valve by means of a liquid other than the liquid under treatment in the bowl, a bearing surface forming a part of the bowl and along which the piston reciprocates, and a complemental bearing surface forming apart of said piston, said bearing surfaces lying annularly entirely within the innermost zone occupied by liquid under treatment within the bowl.

7. A centrifugal separator including a centrifugal bowl provided with a radial discharge opening having direct communication with the separating chamber of the bowl and adapted to be rotated to eflect the continuous discharge of a liquid eiiluent during the concentration of suspended solid material within the bowl, a long and relatively narrow annular groove provided within said bowl, an annular discharge-controlling piston mounted in said groove, a sealing surface beyond the groove adapted to be engaged by an edge of said piston, said piston being adapted to be reciprocated within said groove againstand away from the sealing surface to control the discharge of sludge from the bowl, means for creating hydraulic pressure by means of which the piston is moved to bowl-closing position, and hydraulically operated means for releasing said pressure to permit said piston to be moved to sludge discharging position, said last mentioned means being operated solely by fluid other than that under treatment within the bowl.

8. A centrifugal separator including a centrifugal bowl provided with a discharge openingand 5 adapted to be rotated to efiect the continuous discharge of a liquid efiiuent during the concentration of suspended solid material within the bowl, said bowl being provided with a long and relatively narrow annular groove, an annular dis- 10 charge-controlling piston mounted in said groove and adapted to be reciprocated therein against and away from a sealing surface to control the discharge of sludge from the bowl, means for creating hydraulic pressure by means of which the AAGE NYROP. 

